There is a duct installation structure in which a heater duct for sending warm air into a vehicle interior of an automobile is installed (Patent Document 1).
As shown in FIG. 10, the prior-art duct installation structure is formed by attaching the heater duct 91 to a floor of the vehicle interior and attaching an outlet grill 92 to an outlet opening end portion 911 of the heater duct 91.
The heater duct 91 is a resin molded article obtained by blow molding.
The heater duct 91 is fixed to the floor by a bolt 941 at an iron plate bracket 93 attached to the outlet opening end portion 911 by rivets 931. After the heater duct 91 is attached onto the floor, a floor carpet is laid over the heater duct 91 and then the outlet grill 92 is fixed to the iron plate bracket 93 by bolts 942.
In this way, it is possible to obtain the duct installation structure in which the heater duct 91 is fixed to the floor and the outlet grill 92 is disposed at the outlet opening end portion 911.
In the prior-art duct installation structure, however, the iron plate bracket 93 is attached to the opening end portion 911 of the heater duct 91, which increases the number of parts. As a result, the duct installation structure increases in weight and the cost increases as well. Because the number of parts increases, dimensions of the parts are likely to vary. In other words, dimensional accuracy is required between the heater duct 91 and the iron plate bracket 93 and also between the iron plate bracket 93 and the outlet grill 92, for example, and therefore it is necessary to further reduce dimensional variations of respective component parts.
Patent Document 1: JP 2001-88543 Unexamined Patent Publication (Kokai)